Effects of Chitin Amendments to Soil on Heterodera glycines, Microbial Populations, and Colonization of Cysts by Fungi
Keywords: Biological Control, Nonchemical Control, Ecology, Population Dynamics, Microbial Antagonism, Waste Management
AbstractThe addition of crustacean chitin to soil at rates of 0.5-4.0% (w/w) resulted in control of Heterodera glycines Ichinohe in the roots of 'Ransom' soybean (Glycine max Merr). Total numbers of chitinolytic fungi and actinomycetes in the soil 8 weeks after amendment increased non-linearly in relation to the amount of chitin added in the range of 0-3.0%. Several fungal species isolated from chitin-treated soil are known parasites of nematode eggs in the genera Globodera, Heterodera, and Meloidogyne. The number of cysts of H. glycines colonized by fungi and the number of fungal species in the cysts decreased with increasing levels of chitin in the soil; however, the frequency of occurrence of fungi belonging to the genera Neocosmospora, Paecilomyces, Pythium, and Phytophthora in the cysts was not affected by the amendments.